A Review of Security Requirements for Local Number Portability Administration, The Chertoff Group, September 29, 2014: “For years, Americans have had the legal right to keep their wireless and wireline telephone numbers when switching carriers, and they frequently exercise this right. Carriers must constantly keep track of this switching of carriers in order to route telephone calls correctly. They do this through the nation’s seven Number Portability Administration Centers (“NPACs”),  each of which is operated by a single Local Number Portability Administrator (“LNPA”). Carriers electronically consult information delivered by these NPACs before completing virtually every call and text. Therefore, NPACs are critical to the completion of all telephone calls to numbers that have ever been ported between carriers, and also to numbers that have been updated by the carriers for the purpose of network upgrades and consolidations. They are also essential to local and national law enforcement agencies, which must know on a current and historical basis which carriers are associated with telephone numbers that are subject to lawful search warrants and subpoenas. The NPACs are thus an essential part of the U.S. telecommunications system and critical infrastructure. If NPACs were compromised, telephone calls and text messages might not be completed, many search warrants and subpoenas might not  be served correctly, and our system for prioritizing communications in a national emergency might not function.”